The purpose of the Registry of Comparative Pathology is to collect, classify and study diseases and to utilize knowledge of diseases in many animal species including fish, birds, wild free living mammals, zoo animals, marine mammals, and nonhuman primates in order to benefit mankind. In some instances, these disease processes will act as indicators of environmental factors that may influence human health. In other instances, these diseases will provide new and useful models of human disease that will aid in the understanding of diseases of obscure origin (etiology) in human subjects. The Registry of Comparative Pathology will continue to serve as a unique national resource where constantly increasing tissue collections and illustrative material, all indexed in a "natural language" computerized file are available for study. Emphasis is placed on new diseases of comparative pathological interest. Knowledge emanating from the Registry is disseminated by means of the Comparative Pathology Bulletin, published articles in scientific journals, workshops, symposia, continuing education courses, loan study sets and their syllabi, the publication of animal models both in the American Journal of Pathology and in the Bulletin, and in fascicles in the newly established looseleaf Handbook: Animal Models of Human Disease. The Registry also serves as a study center where interested scientists, both the young and the established who are interested in comparative pathology, can come for extended periods to use the material of the Registry for research training, research or for preparation for teaching. Thus the Registry of Comparative Pathology fills a void in the national medical capability.